Rotating-plate and lever-mounted grinding-roll mill, with upwardlydirecting carrier-air means adjacent the plate periphery



Filed Feb. 7, 1952 y 27, 1954 ERNST-GUENTHER LOESCHE 8 3 ROTATING-PLATEAND LEVER-MOUNTED GRINDING-ROLL MILL, WITH UPWARDLY-DIRECTINGCARRIER-AIR- MEANS ADJACENT THE PLATE PERIPHERY 2 Sheets-Sheet 1 y 7,1954 ERNST-GUENTHER LOESCHE 4,313

ROTATING-PLATE AND LEVER-NOUNTED GRINDING-ROLL MILL, WITHUPWARDLY-DIRECTING CARRIER-AIR MEANS ADJACENT THE PLATE PERIPHERY FiledFeb. 7, 1952 2 Sheets-Sheet 2 V J r2221) 1512101 E. C-ZLoea Che PatentedJuly 27, 1954 ROTATING-PLATE AND LEVER-'MOUNTED GRINDING-ROLL MILL, WITHUPWARDLY- DIRECTING CARRIER-AIR MEANS ADJA- CENT THE PLATE PERIPHERYErnst-Guenther Loesche, Dusseldorf, Germany .Application February '1,1952, Serial No. 270,434

2 Claims.

This invention relates to spring controlled .roller mills having avertical axis, in which on the outside of the grindingplate there isarranged a bladed rim or similar device imparting .a Jde'sire'ddirection to the current of air and having an outer ring which togetherwith a ring provided on the casing ensures tightness. In spring.controlled roller mills of this type, the

periphery of the mill at about the height of the grinding plate. Analready recognized advantage in the use of carrier air consists in thefact that this air produces sifting of the heavy and undesirableconstituents of the material being ground from the other constituentsthereof. In resilient roller mills of known construction, however, itwas difiicult to adjust the speed of the air sufliciently accurately torender possible clear separation of the constituents of the materialbeing ground.

The invention consists in a resilient-roller mill in which the currentof air enters through openings arranged somewhat below the grindingplate. This current of air is then guided through specially shapedchannels under the grinding plate and then passes through a bladed rimprovided on the outside of the grinding plate, or through a similardevice imparting a desired direction to the air stream, into the spaceabove the grinding table, and there takes with it the material which hasbeen sufiiciently finely ground.

In one preferred embodiment of the invention, downwardly inclineddischarge passages are arranged in the base of the spring controlledroller mill, and the channels disposed under the grinding table slopedownwards towards these discharge passages. Thus, undesired constituentssuch as pieces of iron and the like, which because of their highspecific gravity cannot be carried away by the carrier air, can collectin the discharge passages and be emptied out from time to time.

One embodiment of the invention is illustrated by way of example in theaccompanying drawings, in which:

Figure 1 is a view of a roller mill in section, certain parts beingshown in elevation,

Figure 2 is a plan view, in section on section plane 22 of Figure 1,

Figure 3 is a side view, in elevation, of the resilient roller millillustrated in section in Figure 1, and

Figure 4 is a view in elevation, on a larger scale, corresponding to aportion of Figure l, certain parts being shown in section.

Cir

:entryof the carrier air took place along the 2 The main components ofthe spring controlled roller mill illustrated in Figure 1 consist of abasen, which in the embodiment illustrated consists of concrete, but mayalternatively be made of steel, a transmission mechanism 9 accommodatedin the base, an air inlet 0, a grinding plate 0! driven by means of thetransmission mechanism disposed underneath it, and two grinding rollersp whichroll on the rotating grinding plate 11 and are pivotally mountedon shafts 7 through the intermediary of oscillatinglevers sandresiliently pressed against the grinding plate (2 by means of a spring1'.

As mentioned above, the entry of the carrier air takes place throughopenings 0 disposed on two opposite sides of the spring controlledroller mill, as shown in Figures 1 and 3. The inlet openings 0 lead intochannels m disposed below the grinding plate (1. Figure 2 shows thatthese channels m slope downwards towards discharge passages i, two ofwhich are disposed on each side of the spring controlled roller mill(see Figure 2). These discharge passages are each provided, at theoutlet, with a flap 2; attached in a freely rotatable manner at itsupper end only, whereby when fragments accumulate these flaps openspontaneously and therefore have a selfclearing action. On the peripheryof the grinding plate are arranged blades 0 (see Figure 4). On the outeredge of these blades 0 is disposed a continuous ring D which projectsabove the top edge of the blades 0 and together with a ring 1 disposedon the casing produces tightness by reason of the fact that the ring 1overlaps on the inside of the ring 27. The casing a is reinforced atthis point by the arrangement of a plurality of plates. The ring 1 isadapted to the desired course of the current of air and is made ofwear-resistant material, for instance cast electric steel. On the outeredge of the grinding plate 03 is provided a further ring it which isused for retaining the material being ground and is formed as a bulgecorresponding to the desired course of the current of air, and is alsomade of a wear-resistant material. By means of screws 1' this ring it isarranged so as to be vertically adjustable, preferably by the insertionof make-up pieces k. The arrow in Figure 4 shows the required directionof flow of the carrier air.

The grinding plate (1 is provided with specially wear-resistant parts qfixed to the grinding plate at by means of clamping members t. In thecentre of the grinding plate a truncated-conical elevation to isprovided in order to prevent the accumulation of material there.

The arrangement of the grinding rollers p is as follows:

The grinding rollers are each arranged between a pair of oscillatinglevers s (see Figure 3). Resilient pressure of the grinding rollers pagainst the grinding plate (1 is efiected by a pair of springs rdisposed laterally of the mill casing. Alternatively however it ispossible to provide for instance one spring which in that case will passthrough the mill casing itself.

I claim:

1. A spring controlled roller mill for grinding coal, limestone and likematerials, comprising: a casing having lateral air inlets therein, agrinding plate mounted for rotation about a vertical axis within saidcasing, said grinding plate having a fiat grinding surface located abovesaid air inlets, grinding rollers, levers carrying said grinding rollersand mounted to swing about horizontal axes to locate said rollers onsaid flat grinding surface in rolling contact therewith, spring meansapplied to said levers to press the grinding rollers against thegrinding surface for grinding the material during the rotation of thegrinding plate, a peripheral retaining ring on the grinding plateprojecting above the grinding surface thereof, air conduits in saidcasing for conducting air from said air inlets to the underside of thegrinding plate, said air conduits having downwardly and outwardlyinclined bottom walls, peripheral blades on the outside of said grindingplate,

arranged to convey air upwardly from said air conduits to the upper sideof the grinding plate, a continuous shroud ring on the outer edges ofsaid blades, said shroud ring projecting above the top edges of theblades, a ring on the inside of the casing above said blades andoverlapping the projecting part of the shroud ring, and a base undersaid casing having inclined discharge passages therein below said airinlets for the discharge of undesired constituents.

2. A spring controlled roller mill as set forth in claim 1, in which theretaining ring and the ring on the inside of the casing are adapted tocooperate with one another to guide the air current delivered by theblades along the desired path into the space above the grinding surface.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,473,478 Kreutzberg Dec. 25, 1923 2,112,359 Crites Mar. 29,1938 2,206,145 Wood July 2, 1940 2,342,255 Doyle Feb. 22, 1944 2,378,681Bailey June 19, 1945 FOREIGN PATENTS Number Country Date 428,237 GreatBritain May 9, 1935

